There's a lack of consistency and knowledge on the part of most CMs especially regarding the dining plan. This is not a knock against CMs, but more of a reality check. Their training is limited when it comes to very specific questions. General questions can probably be answered by reading the dining plan brochure. Going to Disney's website and doing some searches may help, too. If it's in writing it's pretty safe to believe it; unless, there's been a recent change and everything may not have been updated at the same time.
You can try and call the dining reservation phone number and ask your questions. One trick I've used in the past doing this is to call three times and ask the same question of each CM and see if I get the same answer. If I get the same answer across the board, I feel it's about 95% for sure and I will rely on the answer. The margin of error, here could still burn you, anyway. This does take time to do; so, I choose my questions for this very carefully.
On the boards there are many who have experienced your exact situation and they can be very helpful, probably more helpful than a CM. Although, you can get different answers and opinions, here, too. So, I would use the same rule above and say you are pretty safe if many more have the same answer on the discussion boards.
The best tool is to do both and get a consensus with both and then you cut your margin of error more. That's my two cents worth. Some questions are cut and dry and others have a graytone which are the ones that will be hard to get a good, proper answer. Noone has a PHD in Disney, perse.